pwm: visconti: Make use of devm_pwmchip_alloc() function

This prepares the pwm-visconti driver to further changes of the pwm core
outlined in the commit introducing devm_pwmchip_alloc(). There is no
intended semantical change and the driver should behave as before.

Link: https://lore.kernel.org/r/24e779de69365686bb004742cd8f07cbda131212.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-visconti.c

@@ -34,13 +34,12 @@
 #define PIPGM_PWMC_POLARITY_MASK	GENMASK(5, 5)
 
 struct visconti_pwm_chip {
-	struct pwm_chip chip;
 	void __iomem *base;
 };
 
 static inline struct visconti_pwm_chip *visconti_pwm_from_chip(struct pwm_chip *chip)
 {
-	return container_of(chip, struct visconti_pwm_chip, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
 static int visconti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -134,22 +133,22 @@ static const struct pwm_ops visconti_pwm_ops = {
 static int visconti_pwm_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct pwm_chip *chip;
 	struct visconti_pwm_chip *priv;
 	int ret;
 
-	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
+	chip = devm_pwmchip_alloc(dev, 4, sizeof(*priv));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	priv = visconti_pwm_from_chip(chip);
 
 	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
-	priv->chip.dev = dev;
-	priv->chip.ops = &visconti_pwm_ops;
-	priv->chip.npwm = 4;
+	chip->ops = &visconti_pwm_ops;
 
-	ret = devm_pwmchip_add(&pdev->dev, &priv->chip);
+	ret = devm_pwmchip_add(&pdev->dev, chip);
 	if (ret < 0)
 		return dev_err_probe(&pdev->dev, ret, "Cannot register visconti PWM\n");